What is AEB?
Automatic—or autonomous—emergency braking (AEB) monitors the vehicle’s path for a possible collision. It may first issue a forward-collision warning and, if the driver does not respond sufficiently, apply the brakes.
Its purpose is to help avoid some crashes or reduce their severity. It cannot guarantee a stop or detect every hazard.
How it works
AEB may use a forward camera, radar or both. Some systems are designed primarily for vehicles; others can also respond to pedestrians, cyclists, junction conflicts or reversing hazards within specified conditions.
Capabilities vary substantially by vehicle and speed. The owner’s manual describes the intended targets, operating range and limitations for your exact system.
What the driver may notice
An intervention can include:
- a dashboard or head-up warning
- an urgent sound or steering-wheel vibration
- brake preparation or increased braking assistance
- a short, firm automatic brake application
The driver should respond to the real traffic situation, not wait for the vehicle to act. If the path is clear and braking is inappropriate, keep control and override or steer as the vehicle instructions and circumstances allow.
Common limitations
Detection may be affected by:
- rain, fog, glare, darkness or airborne dust
- a dirty, blocked, damaged or misaligned sensor
- bends, crests and unusual road geometry
- vehicles cutting in suddenly
- small, low, stationary or unusually shaped objects
- pedestrians or cyclists outside the system’s detection conditions
- trailers, loads or accessories that affect sensors
A system can be unavailable without an obvious hardware failure, and some faults or alignment problems may not produce a simple warning code.
Never test it by creating a hazard
Do not drive toward a person, vehicle, wall or improvised target to test AEB. Professional testing requires the correct soft targets, controlled site, measurement equipment and manufacturer procedures.
When braking is unexpected
An apparent false intervention is often called phantom braking. Safely regain control, record the location, speed, weather, warnings and whether cruise control was active. Repeated, severe or post-repair events need systematic inspection.
Repairs and calibration
Windscreen, bumper, grille, body, suspension or wheel-alignment work may disturb inputs used by AEB. Calibration is not automatically required after every job, but the current manufacturer repair procedure must be checked.
Key point
AEB is a valuable last layer of assistance—not a replacement for observation, spacing and timely driver braking.